Process for Producing Hydrogen

ABSTRACT

Process for producing hydrogen where multiple streams are heated in parallel with reformate that has passed from the shift reactor. Each of the multiple streams are heated from a temperature below the dew point of the reformate to a temperature above the dew point of the reformate by reformate that is cooled from a temperature above the dew point of the reformate to a temperature below the dew point of the reformate. The multiple streams can include two or more of water condensate, boiler feed water, hydrocarbon feedstock, and pressure swing adsorption unit by-product gas.

BACKGROUND

Hydrogen production by catalytic steam-hydrocarbon reforming is anenergy intensive process. To improve the energy efficiency of theprocess, reformate formed in the catalytic steam-hydrocarbon reformer ispassed through a series of heat exchangers to recover heat. Thereformate can be used to heat a variety of streams, for example, boilerfeed water, hydrocarbon feedstock, air to the reformer furnace, and fuelto the reformer furnace.

Since the global pinch in the heat exchange network of a catalyticsteam-hydrocarbon reforming process is the dew point of the reformate,using heat exchangers in series causes a constraint on efficientlyrecovering heat from the reformate and may increase equipment cost dueto the required size of the heat exchangers.

Industry desires to produce hydrogen with improved energy efficiency.

BRIEF SUMMARY

There are several aspects of the invention as outlined below. In thefollowing, specific aspects of the invention are outlined below. Thereference numbers and expressions set in parentheses are referring to anexample embodiment explained further below with reference to thefigures. The reference numbers and expressions are, however, onlyillustrative and do not limit the aspect to any specific component orfeature of the example embodiment. The aspects can be formulated asclaims in which the reference numbers and expressions set in parenthesesare omitted or replaced by others as appropriate.

Aspect 1. A process for producing a hydrogen product gas (105), theprocess comprising:

-   -   (a) withdrawing a reformate (25) from a shift reactor (60);    -   (b) heating a water condensate (97) by indirect heat transfer        with the reformate from the shift reactor or a first divided        portion thereof, the water condensate (97) heated from a lower        temperature, T_(WC,lower), to an upper temperature, T_(WC,upper)        when being heated by the reformate or the first divided portion,        and the reformate or first divided portion cooled from an upper        temperature, T_(1,upper), to a lower temperature, T_(1,dower),        when heating the water condensate (97);    -   (c) heating boiler feed water (86) by indirect heat transfer        with the reformate from the shift reactor or a second divided        portion thereof, the boiler feed water (86) heated from a lower        temperature, T_(BFW,lower), to an upper temperature,        T_(BFW,upper) when being heated by the reformate or the second        divided portion, and the reformate or second divided portion        cooled from an upper temperature, T_(2,upper), to a lower        temperature, T_(2,lower), when heating the boiler feed water        (86); where        -   T_(WC,lower), T_(BFW,lower), T_(1,lower), and T_(2,lower),            are less than the dewpoint temperature of the reformate (25)            withdrawn from the shift reactor (60); and        -   T_(WC,upper), T_(BFW,upper), T_(1,upper), and T_(2,upper),            are greater than the dewpoint temperature of the reformate            (25) withdrawn from the shift reactor (60);    -   (d) cooling a mixture comprising at least a portion of the        reformate when the reformate heats the water condensate and the        boiler feed water or comprising at least a portion of the first        divided portion and at least a portion of the second divided        portion when the first divided portion heats the water        condensate and the second divided portion heats the boiler feed        water, the mixture cooled in an amount effective to condense at        least a portion of the water in the mixture to form condensed        water and a water-depleted reformate gas;    -   (e) separating the condensed water from the water-depleted        reformate gas (formed in step (d)) in a separator (90) thereby        forming the water condensate (97) from at least a portion of the        condensed water;    -   (f) passing the water condensate (97) from the separator (90) to        a first heat exchange section (56) for the step of heating the        water condensate by indirect heat transfer with the reformate or        the first divided portion, and passing at least a portion of the        water condensate (97) from the first heat exchange section (56)        to a steam drum (120), (where the water condensate (97) is        passed from the separator (90) to the first heat exchange        section (56) prior to being passed from the first heat exchange        section (56) to the steam drum (120)); and    -   (g) separating a pressure swing adsorption unit feed (95)        comprising at least a portion of the water-depleted reformate        gas in a pressure swing adsorption unit (100) to form the        hydrogen product gas (105) and a pressure swing adsorption unit        by-product gas (115).

Aspect 2. The process of aspect 1 wherein the water condensate (97) isheated by the first divided portion in the first heat exchange section(56) and the boiler feed water is heated by the second divided portionin a second heat exchange section (58).

Aspect 3. The process of aspect 1 or aspect 2, the process furthercomprising:

-   -   passing the reformate from the shift reactor (60) to a        feedstock-heating heat exchanger (70) to heat a hydrocarbon        feedstock (75) by indirect heat transfer with the reformate (25)        in the feedstock-heating heat exchanger (70) and withdrawing the        reformate from the feedstock-heating heat exchanger (70);    -   wherein if the reformate from the shift reactor heats the water        condensate in step (b) and the boiler feed water (86) in step        (c), the reformate from the shift reactor that heats the water        condensate in step (b) and the boiler feed water (86) in        step (c) is the reformate withdrawn from the feedstock-heating        heat exchanger (70); and    -   wherein if the first divided portion of the reformate from the        shift reactor heats the water condensate in step (b) and the        second divided portion of the reformate from the shift reactor        heats the boiler feed water (86) in step (c), the first divided        portion of the reformate from the shift reactor is a first        divided portion of the reformate withdrawn from the        feedstock-heating heat exchanger (70) and the second divided        portion of the reformate from the shift reactor is a second        divided portion of the reformate withdrawn from the        feedstock-heating heat exchanger (70).

Aspect 4. The process of any one of aspects 1 to 3 wherein the watercondensate is heated by the first divided portion of the reformate fromthe shift reactor (60), the process further comprising:

-   -   heating a hydrocarbon feedstock (75) by indirect heat transfer        with the first divided portion, the hydrocarbon feedstock (75)        heated from a lower temperature, T_(HF,lower), to an upper        temperature, T_(HF,upper) when being heated by the first divided        portion; where    -   T_(HF,lower) is less than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60); and    -   T_(HF,upper), is greater than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60).

Aspect 5. The process of any one of aspects 1 to 3 wherein the boilerfeed water is heated by the second divided portion of the reformate fromthe shift reactor (60), the process further comprising:

-   -   heating a hydrocarbon feedstock (75) by indirect heat transfer        with the second divided portion of the reformate from the shift        reactor (60), the hydrocarbon feedstock (75) heated from a lower        temperature, T_(HF,lower), to an upper temperature, T_(HF,upper)        when being heated by the second divided portion; where        -   T_(HF,lower) is less than the dewpoint temperature of the            reformate (25) withdrawn from the shift reactor (60); and        -   T_(HF,upper), is greater than the dewpoint temperature of            the reformate (25) withdrawn from the shift reactor (60).

Aspect 6. The process of any one of aspects 1 to 3, the process furthercomprising:

-   -   (h) heating a hydrocarbon feedstock (75) by indirect heat        transfer with the reformate from the shift reactor (60) or a        divided portion of the reformate (25), the hydrocarbon feedstock        (75) heated from a lower temperature, T_(HF,lower), to an upper        temperature, T_(HF,upper) when being heated by the reformate or        the divided portion, and the reformate or divided portion cooled        from an upper temperature, T_(3,upper), to a lower temperature,        T_(3,lower), when heating the hydrocarbon feedstock (75); where        -   T_(HF,lower) and T_(3,lower) are less than the dewpoint            temperature of the reformate (25) withdrawn from the shift            reactor (60); and        -   T_(HE,upper) and T_(3,upper) are greater than the dewpoint            temperature of the reformate (25) withdrawn from the shift            reactor (60); and    -   wherein the mixture comprises at least a portion of the        reformate when the reformate also heats the hydrocarbon        feedstock or wherein the mixture further comprises at least a        portion of the divided portion of the reformate (25) that heats        the hydrocarbon feedstock when the divided portion heats the        hydrocarbon feedstock.

Aspect 7. The process of aspect 6 wherein the hydrocarbon feedstock (75)is heated by the divided portion in a third heat exchange section (57).

Aspect 8. The process of aspect 6 or aspect 7, the process furthercomprising:

-   -   passing the reformate from the shift reactor (60) to a        feedstock-heating heat exchanger (70) to heat the hydrocarbon        feedstock (75) by indirect heat transfer with the reformate (25)        in the feedstock-heating heat exchanger (70) and withdrawing the        reformate from the feedstock-heating heat exchanger (70);    -   wherein if the reformate from the shift reactor heats the water        condensate in step (b), the boiler feed water (86) in step (c),        and the hydrocarbon feedstock (75) in step (h), the reformate        from the shift reactor that heats the water condensate in step        (b), the boiler feed water (86) in step (c), and the hydrocarbon        feedstock in step (h) is the reformate withdrawn from the        feedstock-heating heat exchanger (70);    -   wherein if the first divided portion of the reformate from the        shift reactor heats the water condensate in step (b), and the        second divided portion of the reformate from the shift reactor        heats the boiler feed water (86) in step (c), and the divided        portion of the reformate from the shift reactor heats the        hydrocarbon feedstock in step (h), the first divided portion of        the reformate from the shift reactor is a first divided portion        of the reformate withdrawn from the feedstock-heating heat        exchanger (70), and the second divided portion is a second        divided portion of the reformate withdrawn from the        feedstock-heating heat exchanger (70), and the divided portion        is a divided portion of the reformate withdrawn from the        feedstock-heating heat exchanger (70); and    -   wherein the hydrocarbon feedstock (75) is heated in step (h)        prior to being heated in the feedstock-heating heat exchanger        (70).

Aspect 9. The process of any one of the previous aspects, the processfurther comprising:

-   -   heating the pressure swing adsorption unit by-product gas (115)        by indirect heat transfer with a divided portion of the        reformate (25) from the shift reactor (60) for heating the        pressure swing adsorption unit by-product gas, the pressure        swing adsorption unit by-product gas (115) heated from a lower        temperature, T_(PSA,lower), to an upper temperature,        T_(PSA,upper) when being heated by the divided portion for        heating the pressure swing adsorption unit by-product gas, and        the divided portion for heating the pressure swing adsorption        unit by-product gas cooled from an upper temperature,        T_(4,upper), to a lower temperature, T_(4,lower), when heating        the pressure swing adsorption unit by-product gas (115); where        -   T_(PSA,lower) and T_(4,lower) are less than the dewpoint            temperature of the reformate (25) withdrawn from the shift            reactor (60); and        -   T_(PSA,upper) and T_(4,upper) are greater than the dewpoint            temperature of the reformate (25) withdrawn from the shift            reactor (60);    -   wherein the mixture further comprises at least a portion of the        divided portion of the reformate that heats the pressure swing        adsorption unit by-product gas.

Aspect 10. The process of aspect 9 wherein the pressure swing adsorptionunit by-product gas (115) is heated by the divided portion that heatsthe pressure swing adsorption unit by-product gas in a fourth heatexchange section (59).

Aspect 11. The process of aspect 9 or aspect 10, the process furthercomprising:

-   -   passing the reformate (25) from the shift reactor (60) to a        feedstock-heating heat exchanger (70), preferably the        feedstock-heating heat exchanger (70) of aspect 3 or aspect 8,        to heat the hydrocarbon feedstock (75) by indirect heat transfer        with the reformate (25) in the feedstock-heating heat exchanger        (70) and withdrawing the reformate from the feedstock-heating        heat exchanger (70); and    -   wherein the divided portion of the reformate that heats the        pressure swing adsorption unit by-product gas is a divided        portion of the reformate withdrawn from the feedstock-heating        heat exchanger (70) that heats the pressure swing adsorption        unit by-product gas.

Aspect 12. The process of any one of aspects 1 to 11 wherein step (f)comprises passing the water condensate (97) from the separator (90) to adeaerator (111), from the deaerator (111) to the first heat exchangesection (56), and from the first heat exchange section (56) to the steamdrum (120), the process further comprising:

-   -   passing the boiler feed water (86) after being heated in        step (c) to a second steam drum (121).

Aspect 13. The process of any one of aspects 1 to 11 wherein step (f)comprises passing the water condensate (97) from the first heat exchangesection (56) to a steam stripper (55), and from the steam stripper (55)to the steam drum (120), the process further comprising:

-   -   passing the boiler feed water (86) after being heated in        step (c) to the steam drum (120).

Aspect 14. The process of any one of the preceding aspects wherein

-   -   the reformate from the shift reactor (60) is divided into the        first divided portion and the second divided portion and,        optionally, one or more additional divided portions from the        shift reactor (60), the first divided portion having a flow        rate, the second divided portion having a flow rate, and, if        present, the one or more additional divided portions each having        a respective flow rate;    -   the water condensate (97) is heated by the first divided portion        in step (b) and the boiler feed water (86) is heated by the        second divided portion in step (c); and wherein    -   the flow rate of the first divided portion from the shift        reactor (60) and the flow rate of the second divided portion        from the shift reactor (60) and, optionally, the flow rates of        the one or more additional divided portions are controlled such        that T_(WC,upper) and T_(BFW,upper) are greater than the        dewpoint temperature of the reformate (25) withdrawn from the        shift reactor (60) and T_(1,lower) and T_(2,lower) are less than        the dewpoint temperature of the reformate (25) withdrawn from        the shift reactor (60).

Aspect 15. The process of the preceding aspect wherein the one or moreadditional divided portions from the shift reactor (60) include adivided portion for heating a hydrocarbon feedstock (75) and/or adivided portion for heating the pressure swing adsorption unitby-product gas (115), the process further comprising the following steps(k) and/or the following steps (I):

-   -   (k) heating a hydrocarbon feedstock (75) by indirect heat        transfer with the divided portion for heating a hydrocarbon        feedstock (75), the hydrocarbon feedstock (75) heated from a        lower temperature, T_(HF,lower), to an upper temperature,        T_(HF,upper), when being heated by the divided portion for        heating a hydrocarbon feedstock (75), and the divided portion        for heating a hydrocarbon feedstock (75) cooled from an upper        temperature, T_(3,upper), to a lower temperature, T_(3,lower),        when heating the hydrocarbon feedstock (75), where T_(HF,lower)        and T_(3,lower) are less than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60) and        T_(HF,upper) and T_(3,upper) are greater than the dewpoint        temperature of the reformate (25) withdrawn from the shift        reactor (60),    -   wherein the flow rates of the one or more additional divided        portions from the shift reactor (60) are controlled such that        T_(HF,upper) is greater than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60) and        T_(3,lower) is less than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60);    -   (l) heating the pressure swing adsorption unit by-product gas        (115) by indirect heat transfer with the divided portion for        heating the pressure swing adsorption unit by-product gas (115),        the pressure swing adsorption unit by-product gas (115) heated        from a lower temperature, T_(PSA,lower), to an upper        temperature, T_(PSA,upper), when being heated by the divided        portion for heating the pressure swing adsorption unit        by-product gas (115), and the divided portion for heating the        pressure swing adsorption unit by-product gas (115) cooled from        an upper temperature, T_(4,upper,) to a lower temperature,        T_(4,lower), when heating the pressure swing adsorption unit        by-product gas (115), where T_(PSA,lower) and T_(4,lower) are        less than the dewpoint temperature of the reformate (25)        withdrawn from the shift reactor (60) and T_(PSA,upper) and        T_(4,upper) are greater than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60),    -   wherein the flow rates of the one or more additional divided        portions from the shift reactor (60) are controlled such that        T_(PSA,upper) is greater than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60) and        T_(4,lower) is less than the dewpoint temperature of the        reformate (25) withdrawn from the shift reactor (60).

Aspect 16. The process of any one of aspects 1, 3, 6, 8, 9, and 10wherein

-   -   the reformate from the shift reactor (60) is conveyed through a        common heat exchanger; and wherein    -   the water condensate (97) and the boiler feed water (86) and,        optionally, a hydrocarbon feedstock (75) and, optionally, the        pressure swing adsorption unit by-product gas (115) are conveyed        each in a respective heat exchange structure extending through        the reformate from the shift reactor (60) in the common heat        exchanger, thereby being heated in parallel indirect heat        exchange with the reformate in the common heat exchanger.

Aspect 17. A process for producing a hydrogen product gas (105), theprocess comprising:

withdrawing a reformate (25) from a shift reactor (60);

heating a water condensate (97) by indirect heat transfer with a firstdivided portion of the reformate from the shift reactor (60), the watercondensate (97) heated from a lower temperature, T_(WC,lower), to anupper temperature, T_(WC,upper) when being heated by the first dividedportion, and the first divided portion cooled from an upper temperature,T_(1,upper), to a lower temperature, T_(1,lower), when heating the watercondensate (97);

-   -   heating boiler feed water (86) by indirect heat transfer with a        second divided portion of the reformate from the shift reactor        (60), the boiler feed water (86) heated from a lower        temperature, T_(BFW,lower), to an upper temperature,        T_(BFW,upper) when being heated by the second divided portion,        and the second divided portion cooled from an upper temperature,        T_(2,upper), to a lower temperature, T_(2,lower), when heating        the boiler feed water (86);    -   heating a hydrocarbon feedstock (75) by indirect heat transfer        with a third divided portion of the reformate (25) from the        shift reactor (60), the hydrocarbon feedstock (75) heated from a        lower temperature, T_(HF,lower), to an upper temperature,        T_(HF,upper) when being heated by the third divided portion, and        the third divided portion cooled from an upper temperature,        T_(3,upper), to a lower temperature, T_(3,lower), when heating        the hydrocarbon feedstock (75); where        -   T_(WC,lower), T_(BFW,lower), T_(HF,lower), T_(1,lower),            T_(2,lower), and T_(3,lower), are less than the dewpoint            temperature of the reformate withdrawn from the shift            reactor; and        -   T_(WC,upper), T_(BFW,upper), T_(HF,upper), T_(1,upper),            T_(2,upper), and T_(3,upper) are greater than the dewpoint            temperature of the reformate withdrawn from the shift            reactor;    -   cooling a mixture comprising at least a portion of the first        divided portion, at least a portion of the second divided        portion, and at least a portion of the third divided portion,        the mixture cooled in an amount effective to condense at least a        portion of the water in the mixture to form condensed water and        a water-depleted reformate gas;    -   separating the condensed water from the water-depleted reformate        gas in a separator (90) thereby forming the water condensate        (97) from at least a portion of the condensed water;    -   passing the water condensate (97) from the separator (90) to a        first heat exchange section (56) for the step of heating the        water condensate by indirect heat transfer with the first        divided portion, and passing at least a portion of the water        condensate (97) from the first heat exchange section (56) to a        steam drum (120), where the water condensate (97) is passed from        the separator (90) to the first heat exchange section (56) prior        to being passed from the first heat exchange section (56) to the        steam drum (120); and separating a pressure swing adsorption        unit feed (95) comprising at least a portion of the        water-depleted reformate gas in a pressure swing adsorption unit        (100) to form the hydrogen product gas (105) and a pressure        swing adsorption unit by-product gas (115).

Aspect 18. The process of aspect 17 further comprising:

-   -   passing the reformate (25) withdrawn from the shift reactor (60)        to a feedstock-heating heat exchanger (70) to heat the        hydrocarbon feedstock (75) by indirect heat transfer with the        reformate (25) in the feedstock-heating heat exchanger (70) and        withdrawing the reformate (25) from the feedstock-heating heat        exchanger (70); and    -   dividing the reformate from the feedstock-heating heat exchanger        (70) to form the first divided portion of the reformate (25)        from the shift reactor (60), the second divided portion of the        reformate (25) from the shift reactor (60), and the third        divided portion of the reformate (25) from the shift reactor        (60).

Aspect 19. A process for producing a hydrogen product gas (105), theprocess comprising:

-   -   withdrawing a reformate (25) from a shift reactor (60);    -   heating a water condensate (97) by indirect heat transfer with a        first divided portion of the reformate from the shift reactor        (60), the water condensate (97) heated from a lower temperature,        T_(WC,lower), to an upper temperature, T_(WC,upper) when being        heated by the first divided portion, and the first divided        portion cooled from an upper temperature, T_(1,upper), to a        lower temperature, T_(1,lower), when heating the water        condensate (97);    -   heating boiler feed water (86) by indirect heat transfer with a        second divided portion of the reformate from the shift reactor        (60), the boiler feed water (86) heated from a lower        temperature, T_(BFW,lower), to an upper temperature,        T_(BFW,upper) when being heated by the second divided portion,        and the second divided portion cooled from an upper temperature,        T_(2,upper), to a lower temperature, T_(2,lower), when heating        the boiler feed water (86);    -   heating a hydrocarbon feedstock (75) by indirect heat transfer        with a third divided portion of the reformate (25) from the        shift reactor (60), the hydrocarbon feedstock (75) heated from a        lower temperature, T_(HF,lower), to an upper temperature,        T_(HF,upper) when being heated by the third divided portion, and        the third divided portion cooled from an upper temperature,        T_(3,upper), to a lower temperature, T_(3,lower), when heating        the hydrocarbon feedstock (75);    -   heating a pressure swing adsorption unit by-product gas (115) by        indirect heat transfer with a fourth divided portion of the        reformate (25) from the shift reactor (60), the pressure swing        adsorption unit by-product gas (115) heated from a lower        temperature, T_(PSA,lower), to an upper temperature,        T_(PSA,upper) when being heated by the fourth divided portion of        the reformate (25), and the fourth divided portion cooled from        an upper temperature, T_(4,upper), to a lower temperature,        T_(4,lower), when heating the pressure swing adsorption unit        by-product gas (115); where        -   T_(WC,lower), T_(BFW,lower), T_(HF,lower), T_(PSA,lower),            T_(1,lower), T_(2,lower), T_(3,lower), and T_(4,lower) are            less than the dewpoint temperature of the reformate (25)            withdrawn from the shift reactor (60); and        -   T_(WC,upper), T_(BFW,upper), T_(HF,upper), T_(PSA,upper),            T_(1,upper), T_(2,upper), T_(3,upper), and T_(4,upper) are            greater than the dewpoint temperature of the reformate (25)            withdrawn from the shift reactor (60);    -   cooling a mixture comprising at least a portion of the first        divided portion, at least a portion of the second divided        portion, at least a portion of the third divided portion, and at        least a portion of the fourth divided portion, the mixture        cooled in an amount effective to condense at least a portion of        the water in the mixture to form condensed water and a        water-depleted reformate gas;    -   separating the condensed water from the water-depleted reformate        gas in a separator (90) thereby forming the water condensate        (97) from at least a portion of the condensed water;    -   passing the water condensate (97) from the separator (90) to a        first heat exchange section (56) for the step of heating the        water condensate by indirect heat transfer with the first        divided portion, and passing at least a portion of the water        condensate (97) from the first heat exchange section (56) to a        steam drum (120), where the water condensate (97) is passed from        the separator (90) to the first heat exchange section (56) prior        to being passed from the first heat exchange section (56) to the        steam drum (120); and    -   separating a pressure swing adsorption unit feed (95) comprising        at least a portion of the water-depleted reformate gas in a        pressure swing adsorption unit (100) to form the hydrogen        product gas (105) and the pressure swing adsorption unit        by-product gas (115).

Aspect 20. The process of aspect 19 further comprising:

-   -   passing the reformate (25) withdrawn from the shift reactor (60)        to a feedstock-heating heat exchanger (70) to heat the        hydrocarbon feedstock (75) by indirect heat transfer with the        reformate (25) in the feedstock-heating heat exchanger (70) and        withdrawing the reformate (25) from the feedstock-heating heat        exchanger (70); and    -   dividing the reformate (25) from the feedstock-heating heat        exchanger (70) to form the first divided portion of the        reformate from the shift reactor (60), the second divided        portion of the reformate from the shift reactor (60), the third        divided portion of the reformate from the shift reactor (60),        and the fourth divided portion of the reformate from the shift        reactor (60).

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a process flow diagram of a catalytic steam-hydrocarbonreforming process.

FIG. 2 is a process flow diagram of a catalytic steam-hydrocarbonreforming process where two separate steam drums are used.

FIG. 3 is a process flow diagram of a comparative catalyticsteam-hydrocarbon reforming process.

FIG. 4 is a process flow diagram of a comparative catalyticsteam-hydrocarbon reforming process where two separate steam drums areused.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The ensuing detailed description provides preferred exemplaryembodiments only, and is not intended to limit the scope, applicability,or configuration of the invention. Rather, the ensuing detaileddescription of the preferred exemplary embodiments will provide thoseskilled in the art with an enabling description for implementing thepreferred exemplary embodiments of the invention, it being understoodthat various changes may be made in the function and arrangement ofelements without departing from scope of the invention as defined by theclaims.

The articles “a” and “an” as used herein mean one or more when appliedto any feature in embodiments of the present invention described in thespecification and claims. The use of “a” and “an” does not limit themeaning to a single feature unless such a limit is specifically stated.The article “the” preceding singular or plural nouns or noun phrasesdenotes a particular specified feature or particular specified featuresand may have a singular or plural connotation depending upon the contextin which it is used.

The adjective “any” means one, some, or all indiscriminately of whateverquantity.

The term “and/or” placed between a first entity and a second entityincludes any of the meanings of (1) only the first entity, (2) only thesecond entity, and (3) the first entity and the second entity. The term“and/or” placed between the last two entities of a list of 3 or moreentities means at least one of the entities in the list including anyspecific combination of entities in this list. For example, “A, B and/orC” has the same meaning as “A and/or B and/or C” and comprises thefollowing combinations of A, B and C: (1) only A, (2) only B, (3) onlyC, (4) A and B and not C, (5) A and C and not B, (6) B and C and not A,and (7) A and B and C.

The phrase “at least one of” preceding a list of features or entitiesmeans one or more of the features or entities in the list of entities,but not necessarily including at least one of each and every entityspecifically listed within the list of entities and not excluding anycombinations of entities in the list of entities. For example, “at leastone of A, B, or C” (or equivalently “at least one of A, B, and C” orequivalently “at least one of A, B, and/or C”) has the same meaning as“A and/or B and/or C” and comprises the following combinations of A, Band C: (1) only A, (2) only B, (3) only C, (4) A and B and not C, (5) Aand C and not B, (6) B and C and not A, and (7) A and B and C.

The term “plurality” means “two or more than two.”

The phrase “at least a portion” means “a portion or all.” The at least aportion of a stream may have the same composition with the sameconcentration of each of the species as the stream from which it isderived. The at least a portion of a stream may have a differentconcentration of species than that of the stream from which it isderived. The at least a portion of a stream may include only specificspecies of the stream from which it is derived.

As used herein a “divided portion” of a stream is a portion having thesame chemical composition and species concentrations as the stream fromwhich it was taken.

As used herein a “separated portion” of a stream is a portion having adifferent chemical composition and different species concentrations thanthe stream from which it was taken.

As used herein, “first,” “second,” “third,” etc. are used to distinguishfrom among a plurality of steps and/or features, and are not indicativeof the total number, or relative position in time and/or space unlessexpressly stated as such.

In the claims, letters may be used to identify claimed steps (e.g. (a),(b), and (c)). These letters are used to aid in referring to the methodsteps and are not intended to indicate the order in which claimed stepsare performed, unless and only to the extent that such order isspecifically recited in the claims.

As used herein, the term “catalyst” refers to a support, catalyticmaterial, and any other additives which may be present on the support.

The term “depleted” means having a lesser mole % concentration of theindicated gas than the original stream from which it was formed.“Depleted” does not mean that the stream is completely lacking theindicated gas.

The terms “rich” or “enriched” means having a greater mole %concentration of the indicated gas than the original stream from whichit was formed.

As used herein, “heat” and “heating” may include both sensible andlatent heat and heating.

As used herein, “indirect heat transfer” is heat transfer from onestream to another stream where the streams are not mixed together.Indirect heat transfer includes, for example, transfer of heat from afirst fluid to a second fluid in a heat exchanger where the fluids areseparated by plates or tubes. Indirect heat transfer includes transferof heat from a first fluid to a second fluid where an intermediateworking fluid is used to carry the heat from the first fluid to thesecond fluid. The first fluid may evaporate a working fluid, e.g. waterto steam, in an evaporator, the working fluid passed to another heatexchanger or condenser, where the working fluid transfers heat to thesecond fluid. Indirect heat transfer from the first fluid to a secondfluid using a working fluid may be accommodated using a heat pipe,thermosyphon, kettle boiler, or the like.

As used herein, “direct heat transfer” is heat transfer from one streamto another stream where the streams are intimately mixed together.Direct heat transfer includes, for example, humidification where wateris sprayed directly into a hot air stream and the heat from the airevaporates the water.

The present invention relates to a process for producing a hydrogenproduct gas. The process utilizes catalytic steam-hydrocarbon reforming.Catalytic steam-hydrocarbon reforming, also called steam methanereforming (SMR), catalytic steam reforming, or steam reforming, isdefined as any process used to convert reformer feedstock into reformateby reaction with steam over a catalyst. Reformate, also called synthesisgas, or simply syngas, as used herein is any mixture comprising hydrogenand carbon monoxide. The reforming reaction is an endothermic reactionand may be described generally as C_(n)H_(m)+n H₂O→n CO+(m/2+n) H₂.Hydrogen is generated when reformate is generated.

The process is described with reference to the figures each showingprocess flow diagrams. Like reference numbers refer to like elementsthroughout the figures. In addition, reference numerals that areintroduced in the specification in association with a drawing figure maybe repeated in one or more subsequent figures without additionaldescription in the specification in order to provide context for otherfeatures.

Process flow diagrams for a catalytic steam-hydrocarbon reformingprocesses suitable for carrying out the present process are shown inFIG. 1 and FIG. 2. FIG. 1 shows a process flow diagram having a singlesteam drum 120, whereas FIG. 2 shows a process flow diagram having twosteam drums, 120 and 121. The process flow diagram of FIG. 2 segregatesboiler feed water formed from process condensate from boiler feed waterformed from make-up water 85. Process condensate may contain organiccompounds. The advantage of using a separate steam drum for the processcondensate and a separate steam drum for boiler feed water formed frommake-up water is to prevent the organic compounds from getting into theexport steam 150. Steam formed from the process condensate may be usedto form feed gas mixture 15 where the presence of the organic compoundscan be easily tolerated.

FIGS. 1 and 2 show required features and optional features, the optionalfeatures providing additional context.

In FIG. 1 and FIG. 2, a reformer feed gas mixture 15 is introduced intoa plurality of catalyst-containing reformer tubes 20 in a reformerfurnace 10, the reformer feed gas mixture 15 is reacted in a reformingreaction under reaction conditions effective to form a reformate 25comprising H₂, CO, CH₄, and H₂O, and the reformate 25 is withdrawn fromthe plurality of catalyst-containing tubes 20 of the reformer furnace10.

The reformer feed gas mixture 15 may be any feed gas mixture suitablefor introducing into a catalytic steam-hydrocarbon reformer for forminga reformate. The reformer feed gas mixture 15 may comprise a hydrocarbonfeedstock 75 that has been desulphurized and steam 151,152, and/or amixture of prereformed hydrocarbon feedstock and steam. Hydrocarbonfeedstock may be natural gas, methane, naphtha, propane, refinery fuelgas, refinery off-gas, or other suitable reformer feedstock known in theart. Prereformed hydrocarbon feedstock and steam is produced in aprereformer (not shown).

The reforming reaction takes place in the plurality ofcatalyst-containing reformer tubes 20 in reformer furnace 10. A reformerfurnace, also called a catalytic steam reformer, steam methane reformer,and steam-hydrocarbon reformer, is defined herein as any fired furnaceused to convert feedstock containing elemental hydrogen and carbon intoreformate by a reaction with steam over a catalyst with heat provided bycombustion of a fuel.

Reformer furnaces with a plurality of catalyst-containing reformertubes, i.e. tubular reformers, are well-known in the art. Any suitablenumber of catalyst-containing reformer tubes may be used. Suitablematerials and methods of construction are known. Catalyst in thecatalyst-containing reformer tubes may be any suitable catalyst known inthe art, for example, a supported catalyst comprising nickel.

The reaction conditions effective to form the reformate 25 in theplurality of catalyst-containing reformer tubes 20 may comprise atemperature ranging from 500° C. to 1000° C. and a pressure ranging from203 kPa to 5,066 kPa (absolute). The reaction condition temperature maybe as measured by any suitable temperature sensor, for example a type Jthermocouple. The reaction condition pressure may be as measured by anysuitable pressure sensor known in the art, for example a pressure gaugeas available from Mensor.

The reformate 25 may exchange heat with a number of streams and may thenbe passed to a shift reactor 60 containing shift catalyst 61. In theexemplary embodiments shown in FIGS. 1 and 2, the reformate 25 withdrawnfrom the plurality of catalyst-containing reformer tubes 20 is passed toheat exchanger 40 (a so-called waste heat boiler) where the reformate 25heats a portion of boiler feed water stream 127 thereby forming atwo-phase water and steam stream that is reintroduced into steam drum120 (FIG. 1) or steam drum 121 (FIG. 2).

In the exemplary embodiments shown in FIGS. 1 and 2, reformate 25 ispassed from heat exchanger 40 to shift reactor 60. The process maycomprise reacting the reformate 25 from heat exchanger 40 in thepresence of a shift catalyst 61 under reaction conditions effective toform additional hydrogen in the reformate 25. Additional hydrogen gasmay be obtained by the catalytic reaction of carbon monoxide and steam.This reaction is exothermic and is commonly referred to as the water-gasshift reaction or shift reaction: CO+H₂O→CO₂+H₂. The reaction isaffected by passing carbon monoxide and water through a bed of asuitable catalyst. The reaction conditions effective to form additionalhydrogen in the reformate 25 may comprise a second temperature rangingfrom 190° C. to 500° C. and a second pressure ranging from 203 kPa to5,066 kPa (absolute).

Any suitable shift catalyst may be used. The shift reactor may be aso-called high temperature shift (HTS), low temperature shift (LTS),medium temperature shift (MTS), or combination. One or more shiftreactors may be used.

For high temperature shift, an inlet temperature in the range 310° C. to370° C., and an outlet temperature in the range 400° C. to 500° C. aretypical. Usually an iron oxide/chromia catalyst is used for hightemperature shift.

For low temperature shift, an inlet temperature in the range 190° C. to230° C., and an outlet temperature in the range 220° C. to 250° C. aretypical. Usually a catalyst comprising metallic copper, zinc oxide, andone or more other difficulty reducible oxides such as alumina or chromiais used for low temperature shift

For medium temperature shift, an inlet temperature in the range 190° C.to 230° C. and an outlet temperature of up to 350° C. are typical. Asuitably formulated supported copper catalyst can be used for mediumtemperature shift. Medium temperature shift may be preferred for theexemplary process.

A combination may include a sequence of high temperature shift, coolingby indirect heat exchange, and low temperature shift. If desired, eithershift stage can be subdivided with interbed cooling.

As shown in the exemplary embodiments in FIGS. 1 and 2, after passingthrough the shift reactor 60, the reformate 25 may be passed to optionalheat exchanger 70 where hydrocarbon feedstock 75 is heated and reformate25 is cooled. Since the articles “a” and “the” mean “one or more,” heatexchanger 70 may comprise one or more heat exchangers.

The reformate 25 from the shift reactor 60 subsequently heats at leasttwo streams in parallel. The reformate may heat the at least two streamsafter being cooled in optional heat exchanger 70.

The water condensate 97 and the boiler feed water 86 are heated inparallel by indirect heat transfer with the reformate from the shiftreactor (after the reformate is cooled in the heat exchanger 70, ifpresent).

The water condensate 97 and the boiler feed water 86 may be heated in acommon heat exchanger (not shown) or the reformate may be divided with afirst divided portion heating the water condensate 97 in a first heatexchange section 56 and a second divided portion heating the boiler feedwater 86 in a second heat exchange section 58. For the case where acommon heat exchanger is used, the common heat exchanger effectivelycontains both heat exchange section 56 and heat exchange section 58. Acommon heat exchanger has essentially the same effect as two separateheat exchangers: one heat exchanger containing heat exchange section 56and a separate heat exchanger containing heat exchange section 58. Thecommon heat exchanger may have separate heat exchange tubes formaintaining separation of the water condensate and the boiler feed water86 so that the reformate heats the water condensate and the boiler feedwater in parallel. In a common heat exchanger the boiler feed water 86and the water condensate 97 and, optionally, one or more further streamsof the process for producing the hydrogen product gas may be conveyedeach through a respective heat exchange structure, such as a respectivetubing system, extending through the reformate from the shift reactor,thereby heating the boiler feed water 86 and the water condensate 97and, optionally, the one or more further streams in parallel indirectheat exchange with the reformate. The reformate is conveyed through thecommon heat exchanger in heat exchange contact with the heat exchangestructures.

Each heat exchange structure conveying one of the process streams to beheated through the common heat exchanger is a respective heat exchangesection of the common heat exchanger. A heat exchange structureconveying water condensate 97 through the common heat exchanger is afirst heat exchange section and a heat exchange structure conveying theboiler feed water 86 through the common heat exchanger is a second heatexchange section of the common heat exchanger. The term “common heatexchanger” is used whenever two or more of the process streams to beheated are conveyed each in a separate heat exchange structure throughan undivided stream of reformate from the shift reactor conveyed throughthat heat exchanger. In a common heat exchanger only the process streamsto be heated are separated from one another whereas the reformate isconveyed through the heat exchanger as an undivided reformate stream.For example, the water condensate 97 may be heated in a first heatexchange section 56 and the boiler feed water 86 may be heated in asecond heat exchange section 58 of the common heat exchanger whereas oneor more further process streams, for example, the hydrocarbon feedstock75 and/or a pressure swing adsorption unit by-product gas 115 may beheated by indirect heat exchange with a divided portion of the reformatefrom the shift reactor each in a further heat exchange section externalto the common heat exchanger for the water condensate 97 and the heatingboiler feed water 86 and in parallel heat exchange to these two processstreams.

The water condensate is heated from a lower temperature, T_(WC,lower),to an upper temperature, T_(WC,upper) when being heated by reformatewhere T_(WC,lower) is less than the dewpoint temperature of thereformate and T_(WC,upper) is greater than the dewpoint temperature ofthe reformate. In case all of the reformate from the shift reactor heatsboth the water condensate 97 and the boiler feed water 86, the reformateis cooled from T_(1,upper) to T_(1,lower) when heating the watercondensate 97. In case the first divided portion of the reformate heatsthe water condensate, the first divided portion of the of the reformateis cooled from T_(1,upper) to T_(1,lower) when heating the watercondensate 97. T_(1, upper) is greater than the dewpoint temperature ofthe reformate and T_(1,lower) is less than the dewpoint temperature ofthe reformate.

The dewpoint temperature or dew point is the temperature at which thewater vapor in the reformate will start to condense out of the gaseousphase at the pressure of the reformate in the respective heat exchangeprocess.

For the instance where the reformate is heating the water condensate,the dewpoint temperature is the dewpoint temperature of the reformate atthe conditions of the reformate when heating the water condensate.Likewise, the dewpoint temperature of the reformate when heating otherstreams is the dewpoint temperature of the reformate at the respectiveconditions of the reformate when heating each respective stream.

The boiler feed water 86 is heated from a lower temperature,T_(BFW,lower), to an upper temperature, T_(BFW,upper) when being heatedby reformate 25, where T_(BFW,lower) is less than the dewpointtemperature of the reformate and T_(BFW,upper) is greater than thedewpoint temperature of the reformate. In case all of the reformate fromthe shift reactor heats both the water condensate 97 and the boiler feedwater 86, the reformate is cooled from T_(2,upper), to T_(2,lower) whenheating the boiler feed water 86. In case the second divided portion ofthe reformate heats the boiler feed water 86, the second divided portionof the of the reformate is cooled from T_(2,upper) to T_(2,lower) whenheating the boiler feed water 86. T_(2,upper) is greater than thedewpoint temperature of the reformate and T_(2,lower) is less than thedewpoint temperature of the reformate.

The water condensate 97 and the boiler feed water 86 are heated inparallel through the dewpoint temperature of the reformate.

The boiler feed water 86 may be formed by heating a water feed 85(so-called make-up water) by indirect heat transfer with reformate 25 inheat exchanger 80, thereby cooling the reformate 25 in heat exchanger80. The water feed 85 may be distilled water, treated water(decalcified, filtered, etc.) or other suitable water known in the art.

After being heated in heat exchanger 80, water feed 85 may be passed todeaerator 110 where dissolved gases are removed. Dissolved gases arestripped from the water feed in the deaerator 110. Steam 11 may beintroduced into the deaerator 110 or steam may be formed in-situ byheating or flashing. Steam aids in stripping the dissolved gases. A ventstream 17 is withdrawn from deaerator 110. The vent stream 17 comprisessteam and gases formed from the dissolved gases stripped from the waterfeed 85. Boiler feed water 86 withdrawn from deaerator 110 may be pumpedto a higher pressure, heated in heat exchange section 58 by indirectheat transfer with the reformate or second portion of the reformate 25,and passed to steam drum 120.

In case the reformate is divided into the first divided portion and thesecond divided portion, the flow rates of the first divided portion andthe second divided portion may be controlled by one or more valves (notshown). The flow rates may be controlled on any basis, e.g. mass, molar,or volume basis. The flow rates may be controlled so that the outlettemperature of the reformate leaving heat exchange section 56 and theoutlet temperature of the reformate leaving heat exchange section 58 areless than the dewpoint temperature of the reformate. The flow rates ofthe divided portions may be controlled so that the outlet temperaturesof the streams being heated are greater than the dewpoint temperatureand at their respective design temperatures.

The hydrocarbon feedstock 75 may be heated in a heat exchanger (notshown) by indirect heat transfer with the reformate that heated both thewater condensate and the boiler feed water, i.e. in series with thereformate that heated both the water condensate and the boiler feedwater. After being heated, the hydrocarbon feedstock may then be passedfrom this heat exchanger to the heat exchanger 70 for further heating ofthe hydrocarbon feedstock.

The hydrocarbon feedstock 75 may be heated in a heat exchanger (notshown) by indirect heat transfer with either the first portion of thereformate 25 from heat exchange section 56 or the second portion of thereformate 25 from heat exchange section 58. The feedstock 75 may then bepassed from this heat exchanger to the heat exchanger 70 for furtherheating of the hydrocarbon feedstock.

A mixture comprising the reformate or the first and second portions ofthe reformate (25), as applicable, is then cooled.

The mixture may be passed to heat exchanger 80 to heat make-up water 85thereby cooling the mixture.

The mixture is cooled in trim cooler 81 in an amount effective tocondense at least a portion of the water in the mixture to formcondensed water and a water-depleted reformate gas.

At least a portion of the water-depleted reformate gas is passed as apressure swing adsorption unit feed 95 to pressure swing adsorption unit100 and separated therein to form hydrogen product gas 105 and pressureswing adsorption unit by-product gas 115.

The condensed water is separated from the water-depleted reformate gasin separator 90 to form water condensate 97 from at least a portion ofthe condensed water. A slip stream of condensed water may be removedfrom the separator, if desired.

Water condensate 97 is passed from separator 90 to heat exchange section56 and at least a portion of water condensate 97 is passed from heatexchange section 56 to steam drum 120. The water condensate 97 is passedfrom the separator 90 to the heat exchange section 56 prior to beingpassed from the heat exchange section 56 to the steam drum 120.

In FIG. 1, water condensate 97 is passed from heat exchange section 56to steam stripper 55 prior to the water condensate 97 being passed tosteam drum 120. Steam from the steam drum 120 or other source is addedto steam stripper 55 to strip organic compounds from the condensate. Thewater condensate 97 portion is passed to steam drum 120. The vapor phasesteam component 152 from stripper 55 is blended with desulphurizedfeedstock 76 and passed as reformer feed gas mixture 15 to the pluralityof catalyst-containing tubes 20.

In FIG. 2, water condensate 97 is passed from separator 90 to heatexchanger 82 to be heated by indirect heat exchange with reformate, andthen passed to deaerator 111 where dissolved gases are removed.Dissolved gases are stripped from the condensate 97 in deaerator 111.Steam 12 may be introduced into the deaerator 111 or steam may be formedin-situ by heating or flashing. Steam may be provided from steam drum121 or any other available steam source. Steam aids in stripping thedissolved gases. A vent stream 18 comprises steam and gases formed fromthe dissolved gases stripped from the condensate 97. Condensate 97 maythen be pumped and passed to heat exchange section 56, and then to steamdrum 120.

To reduce VOC emissions from the hydrogen production facility, thedeaerator vent streams from deaerator 110 and/or deaerator 111 may beinjected into the reformer furnace 10 as described in the “Report onEmission Limits for Rule 1189—Emissions from Hydrogen Plant ProcessVents,” South Coast Air Quality Management District, Jun. 7, 2001(http//www3.aqmd.gov/hb/attachments/2002/020620b.doc), and “FinalEnvironmental Assessment: Proposed Rule 1189—Emissions from HydrogenPlant Process Vents” SCAQMD No. 1189JDNO21199, South Coast Air QualityManagement District Dec. 17, 1999(http://www.aqmd.gov/docs/default-source/ceqa/documents/aqmd-projects/2000/final-ea-for-proposed-amended-rule-1189.doc?sfvrsn=4).

As shown in FIG. 1, when the water condensate is heated in parallel inheat exchange section 56 and stripped by steam in stripper 55, the watercondensate can be pumped and fed directly to a steam drum. A small pumpmay be capable to provide the pressure head needed to pump the watercondensate to a steam drum. The water condensate may be blended withanother water stream before introducing the water condensate into thesteam drum so that the temperature of the water entering the steam drumis at a desirable level.

As shown in FIG. 1 and FIG. 2, the reformate 25 may heat additionalstreams in parallel. The reformate may in addition heat the hydrocarbonfeedstock 75 and/or the pressure swing adsorption unit by-product gas115 in parallel with the water condensate 97 and the boiler feed water86.

The water condensate 97, the boiler feed water 86, and the hydrocarbonfeedstock 75 may be heated in a common heat exchanger (not shown) or thereformate may be divided with a divided portion heating the watercondensate 97 in heat exchange section 56, another divided portionheating the boiler feed water 86 in heat exchange section 58, and yetanother divided portion heating the hydrocarbon feedstock 75 in heatexchange section 57.

In the case where water condensate is heated by the first dividedportion of the reformate in the first heat exchange section 56 in afirst heat exchanger and the boiler feed water is heated by the seconddivided portion of the reformate in the second heat exchange section 58in a second heat exchanger, the hydrocarbon feedstock may be heated in athird heat exchange section where the third heat exchange section 57 isin the same heat exchanger with the first heat exchange section 56 orthe same heat exchanger with the second heat exchange section 58.

The hydrocarbon feedstock 75 may be heated from a lower temperature,T_(HF,lower)) to an upper temperature, T_(HF,upper) when being heated byreformate, where T_(HF,lower) is less than the dewpoint temperature ofthe reformate and T_(HE,upper) is greater than the dewpoint temperatureof the reformate. In case all of the reformate from the shift reactorheats the water condensate 97, the boiler feed water 86, and thehydrocarbon feedstock 75, the reformate is cooled from T_(3,upper) toT_(3,lower) when heating the hydrocarbon feedstock 75. In case a dividedportion of the reformate heats the hydrocarbon feedstock 75, the dividedportion of the of the reformate is cooled from T_(3,upper) toT_(3,lower) when heating the hydrocarbon feedstock 75. T_(3,upper) isgreater than the dewpoint temperature of the reformate and T_(3,lower)is less than the dewpoint temperature of the reformate.

In case the reformate is divided into the multiple divided portions, theflow rates of the divided portions may be controlled by one or morevalves (not shown). For example, the flow rates may be controlled sothat the outlet temperature of the reformate leaving heat exchangesection 56, the outlet temperature of the reformate leaving heatexchange section 57, and the outlet temperature of the reformate leavingheat exchange section 58 are less than the dewpoint temperature of thereformate. The flow rates of the divided portions may also be controlledso that the outlet temperatures of the stream being heated are greaterthan the dewpoint temperature and at their respective designtemperatures.

For the case where a divided portion heats the hydrocarbon feedstock 75in heat exchange section 57, the mixture cooled in heat exchanger 80,which comprises the reformate or the portion that heated the condensateand the portion that heated the boiler feed water, may also comprise thedivided portion that heats the hydrocarbon feedstock 75.

The pressure swing adsorption unit by-product gas 115 may also be heatedby indirect heat transfer with a divided portion of the reformate fromthe shift reactor 60 (by way of heat exchanger 70, if present). Thepressure swing adsorption unit by-product gas 115 may be heated in heatexchange section 59.

The pressure swing adsorption unit by-product gas 115 may be heated froma lower temperature, T_(PSA,lower), to an upper temperature,T_(PSA,upper), when being heated by reformate, where T_(PSA,lower) isless than the dewpoint temperature of the reformate and T_(PSA,upper) isgreater than the dewpoint temperature of the reformate. In case all ofthe reformate from the shift reactor heats the water condensate 97, theboiler feed water 86, and the pressure swing adsorption by-product gas115, the reformate is cooled from T_(4,upper) to T_(4,lower) whenheating the pressure swing adsorption by-product gas 115. In case adivided portion of the reformate heats the pressure swing adsorptionby-product gas 115, the divided portion of the of the reformate iscooled from T_(4,upper) to T_(4,lower) when heating the pressure swingadsorption unit by-product gas 115, where T_(4,upper) is greater thanthe dewpoint temperature of the reformate and T_(4,lower) is less thanthe dewpoint temperature of the reformate.

In case the reformate is divided into the multiple divided portions, theflow rates of the divided portions may be controlled by one or morevalves (not shown). For example, the flow rates may be controlled sothat the outlet temperature of the reformate leaving heat exchangesection 56, the outlet temperature of the reformate leaving heatexchange section 57, if present, the outlet temperature of the reformateleaving heat exchange section 58, and the outlet temperature of thereformate leaving heat exchange section 59 are less than the dewpointtemperature of the reformate. The flow rates may be controlled so thatthe outlet temperatures of the streams being heated are greater than thedewpoint temperature and at their respective design temperatures.

For the case where a divided portion heats the pressure swing adsorptionunit by-product gas 115 in heat exchange section 59, the mixture cooledin heat exchanger 80, which comprises the reformate or the portion thatheated the condensate and the portion that heated the boiler feed water,may also comprise the divided portion that heats the pressure swingadsorption unit by-product gas 115.

As shown in FIG. 1 and FIG. 2, the reformate or a combined streamcomprising divided portions of the reformate heats the make-up water 85in heat exchanger 80. There may be other heat exchangers to heat otherstreams by the reformate as well, such as a heat exchanger (not shown)to generate low pressure steam for deaerator use, and/or a heatexchanger (not shown) to heat recirculating boiler feed water that isused as a heating medium in the process. All these streams, make-upwater plus water condensate in FIG. 2 can be heated in many differentways by the reformate after it has been cooled by heating watercondensate 97 in heat exchanger 56, boiler feed water 86, and optionallyhydrocarbon feedstock 75, and/or pressure swing adsorption unitby-product 115. For example, they can be heated in series by thereformate or the combined stream of all divided portions of thereformate. Or they can be heated in various serial and/or parallelarrangements by four, three or two reformate streams, depending on thenumber of divided portions used for heating water condensate 97 in heatexchanger 56 and boiler feed water 86, and, optionally, hydrocarbonfeedstock 75 and/or pressure swing adsorption unit by-product 115, andhow these divided portions are recombined to form combined reformatestreams.

The hydrocarbon feedstock 75 after being heated by indirect heattransfer with at least a portion of the reformate from the shift reactor60 may be passed to hydrodesulphurization unit 300 to remove sulfur fromthe hydrocarbon feedstock. As is well-known in the art, sulfur maypoison catalyst in the process. Hydrogen 106 for hydrodesulphurizationmay be added to the feedstock before or after heating the hydrocarbonfeedstock 75. Hydrogen product 105 may used to provide hydrogen 106. Atleast a portion 76 of the desulphurized feedstock may be blended withsteam 151, 152 and then further heated by combustion product gas 35 inthe convection section 45 of reformer 10 prior to being introduced intothe catalyst-containing reformer tubes 20 as reformer feed gas mixture15.

A fuel 5 may be combusted with an oxidant gas 3 in a combustion section30 of the reformer furnace 10 external to the plurality ofcatalyst-containing reformer tubes 20 under conditions effective tocombust the fuel 5 to form a combustion product gas 35 comprising CO₂and H₂O. Any suitable burner may be used to introduce the fuel 5 and theoxidant gas 3 into the combustion section 30. Combustion of the fuel 5with the oxidant gas 3 generates heat to supply energy for reacting thereformer feed gas mixture 15 inside the plurality of catalyst-containingreformer tubes 20. The combustion product gas 35 is withdrawn from thecombustion section 30 of the reformer furnace 10 and passed to theconvection section 45 of the reformer furnace to supply heat to otherprocess streams. The combustion section (also called the radiant,radiation, or radiative section) of the reformer furnace is that part ofthe reformer furnace containing the plurality of catalyst-containingreformer tubes. The convection section of the reformer furnace is thatpart of the reformer furnace containing heat exchangers other than theplurality of catalyst-containing reformer tubes. The heat exchangers inthe convection section may be for heating process fluids other thanreformate, such as water/steam, air, pressure swing adsorption unitby-product gas, reformer feed gas prior to introduction into thecatalyst-containing reformer tubes, etc.

Conditions effective to combust the fuel may comprise a temperatureranging from 600° C. to 1500° C. and a pressure ranging from 99 kPa to101.4 kPa (absolute). The temperature may be as measured by athermocouple, an optical pyrometer, or any other calibrated temperaturemeasurement device known in the art for measuring furnace temperatures.The pressure may be as measured by any suitable pressure sensor known inthe art, for example a pressure gauge as available from Mensor.

The fuel 5 may comprise a by-product gas 115 from a pressure swingadsorber 100 and a supplemental fuel 118. By-product gas from a pressureswing adsorber is often called pressure swing adsorber tail gas, andsupplemental fuel is often called trim fuel. The by-product gas 115 andsupplemental fuel 118 may be heated before being used as fuel 5.By-product gas 115 and supplemental fuel 118 may be blended andintroduced together through a burner to the combustion section, or theymay be introduced separately through different ports in the burner.Alternatively, the by-product gas may be introduced through the primaryburner and the supplemental fuel may be introduced through lances nearthe burner.

The oxidant gas 3 is a gas containing oxygen and may be air,oxygen-enriched air, oxygen-depleted air such as gas turbine exhaust,industrial grade oxygen, or any other oxygen-containing gas known foruse in a reformer furnace for combustion. For example, as shown in FIGS.1 and 2, air 130 may be compressed in forced draft fan 135, heated bycombustion product gas 35 in the convection section 45, and passed tothe reformer furnace as oxidant gas 3.

Combustion product gas 35 may heat a number of different process streamsin the convection section 45 of the reformer furnace 10. The combustionproduct gas 35 may heat the streams in various different configurations(order of heating).

FIG. 1 shows the combustion product gas 35 heating the reformer feed gasmixture 15, followed by superheating the steam 125 from steam drum 120.A portion of the superheated steam may be used to form the reformer feedgas mixture 15 and another portion used to form a steam product 150(i.e. export steam). After heating the steam, the combustion product gasthen heats a portion of boiler feed water 127 from steam drum 120 in aheat exchanger to form a two-phase mixture of steam and water of whichat least a portion is returned to the steam drum 120. The combustionproduct gas then heats the combustion oxidant 3. The combustion productgas 35 may then be passed to an induced draft fan 140 and exhausted.

FIG. 2 shows the combustion product gas 35 heating the reformer feed gasmixture 15, followed by superheating the steam 125 from steam drum 121.A portion of the superheated steam may be used to form the reformer feedgas mixture 15 and another portion used to form a steam product 150(i.e. export steam). The combustion product gas then heats a portion ofboiler feed water 127 from steam drum 121 to form a two-phase mixture ofsteam and water of which at least a portion is returned to the steamdrum 121. After heating boiler feed water from steam drum 121, thecombustion product gas heats water condensate from steam drum 120 toform a two-phase mixture of steam and water which is returned to thesteam drum 120. The combustion product gas then heats the combustionoxidant 3. The combustion product gas 35 may then be passed to aninduced draft fan 140 and exhausted.

EXAMPLES

The examples illustrate the benefits of the heat exchanger networks ofthe present invention compared to prior art heat exchange networks.Among the benefits of the present process are the reduced thermal energyconsumption for hydrogen production, reduced heat exchanger capitalcost, and reduced electricity consumption.

The thermal energy consumption for hydrogen production can be comparedusing the net specific energy (NSE) having units J/Nm³, which can bedefined

${{NSE} = \frac{{{HHV}_{fuel}*F_{fuel}} + {{HHV}_{feed}*F_{feed}} - {\Delta \; H*F_{steam}}}{HPR}},$

where

-   -   HHV_(fuel) is the higher heating value of the supplemental fuel        introduced into the combustion section (J/Nm³),    -   F_(fuel) is the flow rate of the fuel (Nm³/h),    -   HHV_(feed) is the higher heating value of the reformer feedstock        introduced into the reformer (J/Nm³),    -   F_(feed) is the flow rate of the reformer feedstock (Nm³/h),    -   ΔH is the enthalpy difference between the export steam and water        at 25° C. (J/kg),    -   F_(steam) is the mass flow of the export steam (kg/h), and    -   HPR is the hydrogen production rate (Nm³/h).

The heat exchanger capital cost can be measured by the sum of the heatexchanger surface area of all heat exchangers (Total Area). The NSE,Total Area and the electricity consumption of all four examples aresummarized in Table 1. The NSE, Total Area, and electricity consumptionof the two comparative examples are set to 100 to make the comparison onthe normalized basis.

Aspen Plus® by Aspen Technology, Inc. was used to simulate the processesdescribed in the examples. Typical conditions for commercial catalyticsteam-hydrocarbon reforming are used, such as natural gas feedstock, asteam-to-carbon ratio of 2.7, and a reformate temperature leaving thecatalyst-containing tubes of 865° C. Each example includes a hightemperature shift reactor and does not include a prereformer. The dewpoint of the reformate downstream of the high temperature shift reactoris about 175° C.

Example 1 Comparative Case

The heat exchange network for example 1 is shown in FIG. 3. Reformate 25exits high temperature shift reactor 60 at 417° C. The heat in thereformate is then recovered by heating various streams. First, thereformate is cooled in heat exchanger 70 to 352° C. while heatinghydrocarbon feedstock 75 from 147° C. to 371° C. The reformate is thenfurther cooled in boiler feed water heat exchanger 78 to 158° C., inwhich the reformate reaches its dew point (175° C.) and the steam in thereformate starts to condense. Boiler feed water 86 is heated in heatexchanger 78 from 109° C. to 232° C. The temperature difference in heatexchanger 78 between the hot and cold streams reaches its allowabledesign minimum (e.g., 11° C.), or pinch, at the dew point of thereformate stream. The reformate then heats feedstock 75 in heatexchanger 77 from 37° C. to 147° C., and the feedstock is then furtherheated in heat exchanger 70 by the reformate to 371° C.

This example shows that both boiler feed water and hydrocarbon feedstockneed to be heated from below the dewpoint temperature of the reformateto above the dewpoint temperature, and this is accomplished by a serialarrangement of boiler feed water heating in heat exchanger 78 sandwichedbetween hydrocarbon feedstock heating in heat exchangers 70 and 77. Itis known that, for the steam reforming process, heat exchange between ahot stream above the dew point of the reformate and a cold stream belowthe dew point (“cross heat exchanger”) will impair thermal efficiency(or increase NSE) and needs to be minimized. In the serial arrangementof example 1, heat exchange between boiler feed water and reformate iscarried out efficiently since heat exchanger 78 is pinched at the dewpoint of the reformate, indicating that “cross heat exchange” isminimized. However, heat exchange between reformate and feedstock inheat exchanger 70 is not efficient because the reformate, which is farabove the dew point (e.g., >352° C.), is used to heat feedstock that isfar below the dew point (e.g., as low as 147° C.). This cross heatexchange results in greater NSE. And it is obvious that cross heatexchange cannot be avoided in a serial arrangement.

Furthermore, in the heat exchange network of FIG. 3, pressure swingadsorption unit by-product gas 115 is heated from 32° C. to 221° C. by asecondary heat source, hot boiler feed water, which is heated by primaryheat sources such as reformate and flue gas. Water condensate 97 isheated and cooled by itself in heat exchanger 53, blended with boilerfeed water, heated in heat exchanger 76, passed to deaerator 110, heatedin heat exchanger 78 by reformate, and passed to steam drum 120. The“repetitive” heating steps for heating pressure swing adsorption unitby-product gas and water condensate result in not only thermalefficiency loss or greater NSE, but also higher capital cost.

The performance of this comparative heat exchange network is summarizedin Table 1 as the basis for comparing to the results for Example 2 whichutilizes an improved heat exchanger network according to the presentinvention.

TABLE 1 Comparison of different heat exchanger networks Example 1Example 2 Example 3 Example 4 Net Specific Energy 100 99.4 100 99.4Total Area 100 90.2 100 99.8 Electricity Consumption 100 99.6 100 95.1

Example 2

The heat exchange network for Example 2 is shown in FIG. 1. Optionalheat exchangers 57 and 59 are used in this example.

Reformate 25 exits high temperature shift reactor 60 at 417° C. The heatin the reformate is then recovered by heating various streams. First,the reformate is cooled in heat exchanger 70 to 368° C. thereby heatinghydrocarbon feedstock 75 from 208° C. to 371° C. The reformate is thendivided into four portions. The first divided portion of the reformateis cooled in heat exchanger 56 to 129° C. thereby heating watercondensate 97 from 38° C. to 247° C. The second divided portion of thereformate is cooled in heat exchanger 58 to 154° C. thereby heating theboiler feed water 86 from 109° C. to 229° C.

The third divided portion of the reformate is cooled in heat exchanger57 to 58° C. thereby heating hydrocarbon feedstock 75 from 37° C. to208° C. The fourth divided portion of the reformate is cooled to 104° C.in heat exchanger 59 thereby heating pressure swing adsorption unitby-product gas 115 from 32° C. to 224° C. The divided fractions for thefirst portion, the second portion, the third portion, and the fourthportion are 0.27, 0.55, 0.07, and 0.11, respectively.

The reformate enters these four heat exchangers above the dew point ofthe reformate and leaves each heat exchanger below the dew point of thereformate. All four cold streams are heated from below the dew point ofthe reformate to above the dew point of the reformate. All four heatexchangers are pinched to the design minimums at the dew point of thereformate. These results indicate that the heat exchange between thereformate and the four cold streams are carried out with minimal crossheat exchange or in the most efficient way that can be achieved, thusresulting in 0.6% reduction in NSE compared to the heat exchange networkin Example 1, as shown in Table 1. Heating water condensate and pressureswing adsorption unit by-product gas by the primary heat source(reformate) also contributes to the NSE reduction, and results in the9.8% reduction in Total Area or heat exchanger capital cost as comparedto the heat exchange network in Example 1. The electricity consumptionis also reduced by 0.4% compared to Example 1, because the pumpingassociated with repetitive heating of process condensate and pressureswing adsorption unit by-product gas is eliminated.

Example 3 Comparative Case with Dual Stream Drums

The process of this comparative example is shown in FIG. 4. With regardto heat exchange, the main difference between this comparative exampleand comparative example 1 is that water condensate 97 and make-up boilerfeed water 86 are heated separately by reformate 25. Example 3 utilizesmultiple stream drums 120 and 121 to segregate boiler feed watercontaining water condensate from boiler feed water made solely from makeup water. The steam made from the make up water is used to make theexport steam 150. Reformate 25 leaves high temperature shift reactor 60at 416° C. and is then used to heat cold streams in series in thefollowing order: hydrocarbon feedstock 75 in heat exchanger 70, watercondensate in heat exchanger 79, make-up boiler feed water in heatexchanger 78, hydrocarbon feedstock 75 in heat exchanger 77, and watercondensate 97 in heat exchanger 76. Table 2 summarizes the temperaturesof the hot and cold streams at the cold and hot ends of each one ofthese heat exchangers.

TABLE 2 Temperature summary for Example 3 Heat Hot End Cold EndExchanger Stream Temp Stream Temp 70 reformate 416 reformate 352feedstock 371 feedstock 149 79 reformate 352 reformate 266 watercondensate 242 water condensate 154 78 reformate 266 reformate 168make-up BFW 215 make-up BFW 109 77 reformate 168 reformate 165 feedstock149 feedstock 37 76 reformate 165 reformate 159 water condensate 153water condensate 109

Similar to the comparative case in Example 1, all four cold streams needto be finally heated to above the dew point of the reformate (175° C.),and this is accomplished by a serial arrangement of heat exchangers. Asshown in Table 2, only make-up boiler feed water heat exchanger 78,among all 5 heat exchangers, experiences the dew point of the reformate,indicating efficient heat transfer between reformate and make-up boilerfeed water. Substantial cross heat exchange occurs in heat exchangers 70and 79, resulting in thermal efficiency loss or high NSE. Again, it isobvious that this cross heat exchange is unavoidable for the serialarrangement of heat exchangers. It can be mitigated by using stagedheating of feedstock (exchangers 77 and 70) and water condensate (heatexchangers 76 and 79); but staging adds to the heat exchange capitalcost or Total Area.

Similar to example 1, pressure swing adsorption unit by-product gas 115in this example is heated, not by a primary heat source, but by hotboiler feed water from 16° C. to 221° C. This repetitive heating costsboth NSE and Total Area.

The performance of this comparative heat exchange network is summarizedin Table 1 as the basis for comparing to the results for Example 4 whichutilizes an improved heat exchanger network according to the presentinvention.

Example 4

The heat exchange network of example 4 is shown in FIG. 2. It is verysimilar to Example 2 since water condensate is already heated thereseparately from make-up boiler feed water. Reformate 25 leaves hightemperature shift reactor 60 at 417° C. The heat in the reformate isthen recovered by heating various streams. First, it is cooled in heatexchanger 70 to 368° C. thereby heating feedstock 75 from 222° C. to371° C. The reformate is then divided into four portions. The firstdivided portion of the reformate stream is cooled in heat exchanger 56to 162° C. thereby heating water condensate 97 from 115° C. to 242° C.The second divided portion of the reformate stream is cooled in heatexchanger 58 to 162° C. thereby heating the boiler feed water from 110°C. to 250° C. The third portion of the reformate stream is cooled inheat exchanger 57 to 18° C. thereby heating feedstock 75 from 5° C. to222° C. The fourth divided portion of the reformate is cooled to 114° C.in heat exchanger 59 thereby heating pressure swing adsorption unitby-product gas 115 from 16° C. to 232° C. The divided fractions for thefirst portion, the second portion, the third portion, and the fourthportion are 0.36, 0.45, 0.08, and 0.11, respectively.

Similar to Example 2, the heat exchange between the reformate and thefour cold streams are carried out in the most efficient way that can beachieved. As shown in Table 1, the benefits of this heat exchangenetwork include 0.6% reduction in NSE, 0.2% reduction in Total Area and4.9% reduction in electricity consumption compared to the comparativecase in Example 3.

We claim:
 1. A process for producing a hydrogen product gas, the processcomprising: (a) withdrawing a reformate from a shift reactor, thereformate comprising H₂O, H₂, CO, and CO₂; (b) heating a watercondensate by indirect heat transfer with the reformate from the shiftreactor or a first divided portion thereof, the water condensate heatedfrom a lower temperature, T_(WC,lower), to an upper temperature,T_(WC,upper), when being heated by the reformate or the first dividedportion, and the reformate or first divided portion cooled from an uppertemperature, T_(1,upper), to a lower temperature, T_(1,lower), whenheating the water condensate; (c) heating boiler feed water by indirectheat transfer with the reformate from the shift reactor or a seconddivided portion thereof, the boiler feed water heated from a lowertemperature, T_(BFW,lower), to an upper temperature, T_(BFW,upper), whenbeing heated by the reformate or the second divided portion, and thereformate or second divided portion cooled from an upper temperature,T_(2,upper), to a lower temperature, T_(2,lower), when heating theboiler feed water; where T_(WC,lower), T_(BFW,lower), T_(1,lower), andT_(2,lower), are less than the dewpoint temperature of the reformatewithdrawn from the shift reactor; and T_(WC,upper), T_(BFW,upper),T_(1,upper), and T_(2,upper), are greater than the dewpoint temperatureof the reformate withdrawn from the shift reactor; (d) cooling a mixturecomprising at least a portion of the reformate when the reformate heatsthe water condensate and the boiler feed water or comprising at least aportion of the first divided portion and at least a portion of thesecond divided portion when the first divided portion heats the watercondensate and the second divided portion heats the boiler feed water,the mixture cooled in an amount effective to condense at least a portionof the water in the mixture to form condensed water and a water-depletedreformate gas; (e) separating the condensed water from thewater-depleted reformate gas in a separator thereby forming the watercondensate from at least a portion of the condensed water; (f) passingthe water condensate from the separator to a first heat exchange sectionfor the step of heating the water condensate by indirect heat transferwith the reformate or the first divided portion, and passing at least aportion of the water condensate from the first heat exchange section toa steam drum; and (g) separating a pressure swing adsorption unit feedcomprising at least a portion of the water-depleted reformate gas in apressure swing adsorption unit to form the hydrogen product gas and apressure swing adsorption unit by-product gas.
 2. The process of 1wherein the water condensate is heated by the first divided portion inthe first heat exchange section and the boiler feed water is heated bythe second divided portion in a second heat exchange section.
 3. Theprocess of claim 1, the process further comprising: passing thereformate withdrawn from the shift reactor to a feedstock-heating heatexchanger to heat a hydrocarbon feedstock by indirect heat transfer withthe reformate in the feedstock-heating heat exchanger and withdrawingthe reformate from the feedstock-heating heat exchanger; wherein if thereformate from the shift reactor heats the water condensate in step (b)and the boiler feed water in step (c), the reformate from the shiftreactor that heats the water condensate in step (b) and the boiler feedwater in step (c) is the reformate withdrawn from the feedstock-heatingheat exchanger; and wherein if the first divided portion of thereformate from the shift reactor heats the water condensate in step (b)and the second divided portion of the reformate from the shift reactorheats the boiler feed water in step (c), the first divided portion ofthe reformate from the shift reactor is a first divided portion of thereformate withdrawn from the feedstock-heating heat exchanger and thesecond divided portion of the reformate from the shift reactor is asecond divided portion of the reformate withdrawn from thefeedstock-heating heat exchanger.
 4. The process of claim 1 wherein thewater condensate is heated by the first divided portion of the reformatefrom the shift reactor, the process further comprising: heating ahydrocarbon feedstock by indirect heat transfer with the first dividedportion, the hydrocarbon feedstock heated from a lower temperature,T_(HF,lower), to an upper temperature, T_(HF,upper) when being heated bythe first divided portion; where T_(HF,lower) is less than the dewpointtemperature of the reformate withdrawn from the shift reactor; andT_(HF,upper), is greater than the dewpoint temperature of the reformatewithdrawn from the shift reactor.
 5. The process of claim 1 wherein theboiler feed water is heated by the second divided portion of thereformate from the shift reactor, the process further comprising:heating a hydrocarbon feedstock by indirect heat transfer with thesecond divided portion of the reformate from the shift reactor, thehydrocarbon feedstock heated from a lower temperature, T_(HF,lower), toan upper temperature, T_(HF,upper), when being heated by the seconddivided portion; where T_(HF,lower) is less than the dewpointtemperature of the reformate withdrawn from the shift reactor; andT_(HF,upper) is greater than the dewpoint temperature of the reformatewithdrawn from the shift reactor.
 6. The process of claim 1, the processfurther comprising: (h) heating a hydrocarbon feedstock by indirect heattransfer with the reformate from the shift reactor or a divided portionof the reformate, the hydrocarbon feedstock heated from a lowertemperature, T_(HF,lower), to an upper temperature, T_(HF,upper), whenbeing heated by the reformate or the divided portion, and the reformateor divided portion cooled from an upper temperature, T_(3,upper), to alower temperature, T_(3,lower), when heating the hydrocarbon feedstock;where T_(HF,lower) and T_(3,lower) are less than the dewpointtemperature of the reformate withdrawn from the shift reactor; andT_(HF,upper) and T_(3,upper) are greater than the dewpoint temperatureof the reformate withdrawn from the shift reactor; wherein the mixturecomprises at least a portion of the reformate when the reformate alsoheats the hydrocarbon feedstock or wherein the mixture further comprisesat least a portion of the divided portion of the reformate that heatsthe hydrocarbon feedstock when the divided portion heats the hydrocarbonfeedstock.
 7. The process of claim 6 wherein the hydrocarbon feedstockis heated by the divided portion in a third heat exchange section. 8.The process of claim 6, the process further comprising: passing thereformate withdrawn from the shift reactor to a feedstock-heating heatexchanger to heat the hydrocarbon feedstock by indirect heat transferwith the reformate in the feedstock-heating heat exchanger andwithdrawing the reformate from the feedstock-heating heat exchanger;wherein if the reformate from the shift reactor heats the watercondensate in step (b), the boiler feed water in step (c), and thehydrocarbon feedstock in step (h), the reformate from the shift reactorthat heats the water condensate in step (b), the boiler feed water instep (c), and the hydrocarbon feedstock in step (h) is the reformatewithdrawn from the feedstock-heating heat exchanger; wherein if thefirst divided portion of the reformate from the shift reactor heats thewater condensate in step (b), and the second divided portion of thereformate from the shift reactor heats the boiler feed water in step(c), and the divided portion of the reformate from the shift reactorheats the hydrocarbon feedstock in step (h), the first divided portionof the reformate from the shift reactor is a first divided portion ofthe reformate withdrawn from the feedstock-heating heat exchanger, andthe second divided portion is a second divided portion of the reformatewithdrawn from the feedstock-heating heat exchanger, and the dividedportion is a divided portion of the reformate withdrawn from thefeedstock-heating heat exchanger; and wherein the hydrocarbon feedstockis heated in step (h) prior to being heated in the feedstock-heatingheat exchanger.
 9. The process of claim 1, the process furthercomprising: heating the pressure swing adsorption unit by-product gas byindirect heat transfer with a divided portion of the reformate from theshift reactor for heating the pressure swing adsorption unit by-productgas, the pressure swing adsorption unit by-product gas heated from alower temperature, T_(PSA,lower), to an upper temperature, T_(PSA,upper)when being heated by the divided portion for heating the pressure swingadsorption unit by-product gas, and the divided portion for heating thepressure swing adsorption unit by-product gas cooled from an uppertemperature, T_(4,upper), to a lower temperature, T_(4,lower), whenheating the pressure swing adsorption unit by-product gas; whereT_(PSA,lower) and T_(4,lower) are less than the dewpoint temperature ofthe reformate withdrawn from the shift reactor; and T_(PSA,upper) andT_(4,upper) are greater than the dewpoint temperature of the reformatewithdrawn from the shift reactor; wherein the mixture further comprisesat least a portion of the divided portion of the reformate that heatsthe pressure swing adsorption unit by-product gas.
 10. The process ofclaim 9 wherein the pressure swing adsorption unit by-product gas isheated by the divided portion that heats the pressure swing adsorptionunit by-product gas in a fourth heat exchange section.
 11. The processof claim 9, the process further comprising: passing the reformatewithdrawn from the shift reactor to a feedstock-heating heat exchangerto heat the hydrocarbon feedstock by indirect heat transfer with thereformate in the feedstock-heating heat exchanger and withdrawing thereformate from the feedstock-heating heat exchanger; and wherein thedivided portion of the reformate that heats the pressure swingadsorption unit by-product gas is a divided portion of the reformatewithdrawn from the feedstock-heating heat exchanger that heats thepressure swing adsorption unit by-product gas.
 12. The process of claim1 wherein step (f) comprises passing the water condensate from theseparator to a deaerator, from the deaerator to the first heat exchangesection, and from the first heat exchange section to the steam drum, theprocess further comprising: passing the boiler feed water after beingheated in step (c) to a second steam drum.
 13. The process of claim 1wherein step (f) comprises passing the water condensate from the firstheat exchange section to a steam stripper, and from the steam stripperto the steam drum, the process further comprising: passing the boilerfeed water after being heated in step (c) to the steam drum.
 14. Theprocess of claim 1 wherein: the reformate from the shift reactor isdivided into the first divided portion and the second divided portionand, optionally, one or more additional divided portions from the shiftreactor, the first divided portion having a flow rate, the seconddivided portion having a flow rate, and, if present, the one or moreadditional divided portions each having a respective flow rate; thewater condensate is heated by the first divided portion in step (b) andthe boiler feed water is heated by the second divided portion in step(c); and wherein the flow rate of the first divided portion from theshift reactor and the flow rate of the second divided portion, andoptionally, the flow rates of the one or more additional dividedportions from the shift reactor are controlled such that T_(WC,upper)and T_(BFW,upper) are greater than the dewpoint temperature of thereformate withdrawn from the shift reactor and T_(1,lower) andT_(2,lower) are less than the dewpoint temperature of the reformatewithdrawn from the shift reactor.
 15. The process of claim 14 whereinthe one or more additional divided portions from the shift reactorinclude a divided portion for heating a hydrocarbon feedstock, theprocess further comprising: heating the hydrocarbon feedstock byindirect heat transfer with the divided portion for heating ahydrocarbon feedstock, the hydrocarbon feedstock heated from a lowertemperature, T_(HF,lower), to an upper temperature, T_(HF,upper), whenbeing heated by the divided portion for heating a hydrocarbon feedstock,and the divided portion for heating a hydrocarbon feedstock cooled froman upper temperature, T_(3,upper), to a lower temperature, T_(3,lower),when heating the hydrocarbon feedstock, where T_(HF,lower) andT_(3,lower) are less than the dewpoint temperature of the reformatewithdrawn from the shift reactor and T_(HF,upper) and T_(3,upper) aregreater than the dewpoint temperature of the reformate withdrawn fromthe shift reactor, wherein the flow rate of the divided portion forheating the hydrocarbon feedstock is controlled such that T_(HF,upper)is greater than the dewpoint temperature of the reformate withdrawn fromthe shift reactor and T_(3,lower) is less than the dewpoint temperatureof the reformate withdrawn from the shift reactor.
 16. The process ofclaim 14 wherein the one or more additional divided portions from theshift reactor include a divided portion for heating the pressure swingadsorption unit by-product gas, the process further comprising: heatingthe pressure swing adsorption unit by-product gas by indirect heattransfer with the divided portion for heating the pressure swingadsorption unit by-product gas, the pressure swing adsorption unitby-product gas heated from a lower temperature, T_(PSA,lower), to anupper temperature, T_(PSA,upper), when being heated by the dividedportion for heating the pressure swing adsorption unit by-product gas,and the divided portion for heating the pressure swing adsorption unitby-product gas cooled from an upper temperature, T_(4,upper), to a lowertemperature, T_(4,lower), when heating the pressure swing adsorptionunit by-product gas, where T_(PSA,lower) and T_(4,lower) are less thanthe dewpoint temperature of the reformate withdrawn from the shiftreactor and T_(PSA,upper) and T_(4,upper) are greater than the dewpointtemperature of the reformate withdrawn from the shift reactor, whereinthe flow rate of the divided portion for heating the pressure swingadsorption unit by-product gas is controlled such that T_(PSA,upper) isgreater than the dewpoint temperature of the reformate withdrawn fromthe shift reactor and T_(4,lower) is less than the dewpoint temperatureof the reformate withdrawn from the shift reactor.
 17. A process forproducing a hydrogen product gas, the process comprising: withdrawing areformate from a shift reactor; heating a water condensate by indirectheat transfer with a first divided portion of the reformate from theshift reactor, the water condensate heated from a lower temperature,T_(WC,lower), to an upper temperature, T_(WC,upper) when being heated bythe first divided portion, and the first divided portion cooled from anupper temperature, T_(1,upper), to a lower temperature, T_(1,lower),when heating the water condensate; heating boiler feed water by indirectheat transfer with a second divided portion of the reformate from theshift reactor, the boiler feed water heated from a lower temperature,T_(BFW,lower), to an upper temperature, T_(BFW,upper) when being heatedby the second divided portion, and the second divided portion cooledfrom an upper temperature, T_(2,upper), to a lower temperature,T_(2,lower), when heating the boiler feed water; heating a hydrocarbonfeedstock by indirect heat transfer with a third divided portion of thereformate from the shift reactor, the hydrocarbon feedstock heated froma lower temperature, T_(HF, lower), to an upper temperature,T_(HF,upper) when being heated by the third divided portion, and thethird divided portion cooled from an upper temperature, T_(3,upper), toa lower temperature, T_(3,lower), when heating the hydrocarbonfeedstock; where T_(WC,lower), T_(BFW,lower), T_(HF,lower), T_(1,lower),T_(2,lower), and T_(3,lower), are less than the dewpoint temperature ofthe reformate withdrawn from the shift reactor; and T_(WC,upper),T_(BFW,upper), T_(HF,upper), T_(1,upper), T_(2,upper), and T_(3,upper)are greater than the dewpoint temperature of the reformate withdrawnfrom the shift reactor; cooling a mixture comprising at least a portionof the first divided portion, at least a portion of the second dividedportion, and at least a portion of the third divided portion, themixture cooled in an amount effective to condense at least a portion ofthe water in the mixture to form condensed water and a water-depletedreformate gas; separating the condensed water from the water-depletedreformate gas in a separator thereby forming the water condensate fromat least a portion of the condensed water; passing the water condensatefrom the separator to a first heat exchange section for the step ofheating the water condensate by indirect heat transfer with the firstdivided portion, and passing at least a portion of the water condensatefrom the first heat exchange section to a steam drum, where the watercondensate is passed from the separator to the first heat exchangesection prior to being passed from the first heat exchange section tothe steam drum; and separating a pressure swing adsorption unit feedcomprising at least a portion of the water-depleted reformate gas in apressure swing adsorption unit to form the hydrogen product gas and apressure swing adsorption unit by-product gas.
 18. The process of claim17 further comprising: passing the reformate withdrawn from the shiftreactor to a feedstock-heating heat exchanger to heat the hydrocarbonfeedstock by indirect heat transfer with the reformate in thefeedstock-heating heat exchanger and withdrawing the reformate from thefeedstock-heating heat exchanger; and dividing the reformate from thefeedstock-heating heat exchanger to form the first divided portion ofthe reformate from the shift reactor, the second divided portion of thereformate from the shift reactor, and the third divided portion of thereformate from the shift reactor.
 19. A process for producing a hydrogenproduct gas, the process comprising: withdrawing a reformate from ashift reactor; heating a water condensate by indirect heat transfer witha first divided portion of the reformate from the shift reactor, thewater condensate heated from a lower temperature, T_(WC,lower), to anupper temperature, T_(WC,upper) when being heated by the first dividedportion, and the first divided portion cooled from an upper temperature,T_(1,upper), to a lower temperature, T_(1,lower), when heating the watercondensate; heating boiler feed water by indirect heat transfer with asecond divided portion of the reformate from the shift reactor, theboiler feed water heated from a lower temperature, T_(BFW,lower), to anupper temperature, T_(BFW,upper) when being heated by the second dividedportion, and the second divided portion cooled from an uppertemperature, T_(2,upper), to a lower temperature, T_(2,lower), whenheating the boiler feed water; heating a hydrocarbon feedstock byindirect heat transfer with a third divided portion of the reformatefrom the shift reactor, the hydrocarbon feedstock heated from a lowertemperature, T_(HF,lower), to an upper temperature, T_(HF,upper) whenbeing heated by the third divided portion, and the third divided portioncooled from an upper temperature, T_(3,upper), to a lower temperature,T_(3,lower), when heating the hydrocarbon feedstock; heating thepressure swing adsorption unit by-product gas by indirect heat transferwith a fourth divided portion of the reformate from the shift reactor,the pressure swing adsorption unit by-product gas heated from a lowertemperature, T_(PSA,lower), to an upper temperature, T_(PSA,upper) whenbeing heated by the fourth divided portion of the reformate, and thefourth divided portion cooled from an upper temperature, T_(4,upper), toa lower temperature, T_(4,lower), when heating the pressure swingadsorption unit by-product gas; where T_(WC,lower), T_(BFW,lower),T_(HF,lower), T_(PSA,lower), T_(1,lower), T_(2,lower), T_(3,lower), andT_(4,lower) are less than the dewpoint temperature of the reformatewithdrawn from the shift reactor; and T_(WC,upper), T_(BFW,upper),T_(HF,upper), T_(PSA,upper), T_(1,upper), T_(2,upper), T_(3,upper), andT_(4,upper) are greater than the dewpoint temperature of the reformatewithdrawn from the shift reactor; cooling a mixture comprising at leasta portion of the first divided portion, at least a portion of the seconddivided portion, at least a portion of the third divided portion, and atleast a portion of the fourth divided portion, the mixture cooled in anamount effective to condense at least a portion of the water in themixture to form condensed water and a water-depleted reformate gas;separating the condensed water from the water-depleted reformate gas ina separator thereby forming the water condensate from at least a portionof the condensed water; passing the water condensate from the separatorto a first heat exchange section for the step of heating the watercondensate by indirect heat transfer with the first divided portion, andpassing at least a portion of the water condensate from the first heatexchange section to a steam drum, where the water condensate is passedfrom the separator to the first heat exchange section prior to beingpassed from the first heat exchange section to the steam drum; andseparating a pressure swing adsorption unit feed comprising at least aportion of the water-depleted reformate gas in a pressure swingadsorption unit to form the hydrogen product gas and a pressure swingadsorption unit by-product gas.
 20. The process of claim 19 furthercomprising: passing the reformate withdrawn from the shift reactor to afeedstock-heating heat exchanger to heat the hydrocarbon feedstock byindirect heat transfer with the reformate in the feedstock-heating heatexchanger and withdrawing the reformate from the feedstock-heating heatexchanger; and dividing the reformate from the feedstock-heating heatexchanger to form the first divided portion of the reformate from theshift reactor, the second divided portion of the reformate from theshift reactor, the third divided portion of the reformate from the shiftreactor, and the fourth divided portion of the reformate from the shiftreactor.